• Journal of Dairy Science and Biotechnology
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• 제22권1호
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• pp.27-35
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• 2004

The shelf lift of market milk should be determined based on the flavor which is influenced by environmental and sanitary conditions of dairy farm, milk processing plant, and storage and transportation facility as well as compositional quality, such as protein and fat, of the milk itself. The legal shelf life of market milk is often limited by microbiological quality, e.g. total bacterial count, coliform count, and food poisoning bacteria. The bacteria involved with milk spoilage and poisoning are originated from bacteria contaminating milk after pasteurization or spores surviving the heat treatment of pasteurization. The important factors which influence the shelf life of market milk are microbiological quality of raw milk, pasteurization condition, post-pasteurization contamination, and temperature during storage and transportation. The organoleptic quality and shelf life of market milk should be further improved by satisfying the consumer's taste, which depends on somatic cell count and bacterial count of milk, feed quality, foreign substance in milk, and physical treatment during processing and transportation.

• 한국축산식품학회지
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• 제32권5호
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• pp.540-544
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• 2012

During heat treatment and storage of milk, deteriorative reaction takes place, which consequently influence on the milk quality. In this study, formation of lactulose and furosine under different thermal conditions and storage conditions, and the ratio of lactulose and furosine (LU/FU) in presence of reconstituted milk powder were determined to establish chemical indicators for heat damages of milk and the adulteration of fresh milk in dairy field. The lactulose and furosine contents linearly increased with increased heating temperature and heating time. It showed high correlation between the formation of lactulose and furosine, and the treatment temperature and time (p<0.05). The lactulose and furosine concentration of HTST milk and UHT milk noticeably increased during storage at $30^{\circ}C$, but there was no noticeable increase of lactulose and furosine concentration at lower storage temperature. In the raw milk, the lactulose and furosine contents greatly increased with the addition of reconstituted milk. The increase level of furosine was much higher than that of lactulose, which consequently resulted in the lower LU/FU ratio in milk as increase of added reconstituted milk amounts. As comparing with raw milk, there was more than twice reduction in LU/FU ratios after the addition of reconstituted milk (p<0.05). It can be concluded that lactulose and furosine are suitable milk quality indicators of heat damage and for demonstrating improper addition of reconstituted milk powder.

• Journal of Dairy Science and Biotechnology
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• 제14권2호
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• pp.185-193
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• 1996

This study was to investigate principle of freeze concentration such as nucleation, crystal growth and procedure of freeze concentration, essential factor and application of freeze concentration. Especially, quality of milk was emphasized. For exemple, in sensory evaluation of freeze concentrated and reconstituted skim milk and whole milk, taste, color, mouth feel and texture were superior to control. Recently developed technique of freeze concentration for quality milk and dairy products may be expected for advanced quality of various milk and dairy products in near future.

• 한국동물위생학회지
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• 제41권2호
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• pp.63-69
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• 2018

This study was conducted to evaluate the effect of tuberculin test and associated various environmental factors on the quantity and quality of milk production of daily cows. The change of milk quantity followed to tuberculin test was investigated on 109 daily farms in south Gyeonggi, and the change of milk quality was also studied on 48 daily farms. The result of this study showed that the quantity and quality of milk production was decreased after tuberculin test (P<0.05). The amount of loss of the milk production due to tuberculin test was, however, only 0.92 L per cow. In terms of milk quality, the level of total protein was statistically significantly decreased. This study also showed that the milk quality was further decreased when the cows were restraint after veterinarians arrived compared to the case that cows were stayed restraint before the veterinarians visited the farm. In addition, milk quality and quantity were lowered worse when relative humidity of the location of tuberculin test was lower than 50% or higher than 70%, or when the milk production of a farm is higher than its quarter. This study showed that stress on daily cows and the farmers induces the decrease of milk yield and milk quality, and these losses can be minimized by regulating various environmental factors to the direction to maximize productivity.

• Journal of Dairy Science and Biotechnology
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• 제19권1호
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• pp.13-21
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• 2001

Milk can be regarded as a complete food, containing protein, fat, lactose, vitamins and minerals. Milk is heated for a variety of reasons. The main reasons are: to remove pathogenic organisms; to increase shelf-life. But, when milk is heated, many changes take place: denaturation of whey proteins and interaction with casein, Maillard browning, losses of vitamin and minerals. The addition of a additive and milk powder to flavor and taste may cause undesirable change of quality during heating milk. The reconstituted milk is the milk product resulting from the addition of water to the dried or condensed form in the amount necessary to re-establish the specified water solids ratio. Therefore, according to the increasement of consumption of processed milk, the necessity for study about the quality of processed milk mixed with reconstituted milk arose.

• Journal of Dairy Science and Biotechnology
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• 제35권1호
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• pp.55-72
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• 2017

The second article of 'Effects of heat treatment on the nutritional quality of milk,' titled 'Destruction of microorganisms in milk by heat treatment' and authored by Dr. Seong Kwan Cha, who worked at the Korea Food Research Institute, covers the heat-stable microorganisms that exist in milk after pasteurization. The article focusses on the microbiological quality of raw milk and market milk following heat treatment, and is divided into four sub-topics: microbiological quality of raw milk, survey and measurement of microorganisms killed in raw milk, effect on psychrophilic and mesophilic microorganisms, and effect of heat treatment methods on thermoduric microorganisms. Bacillus spp. and Clostridium spp. are sporeforming gram-positive organisms commonly found in soil, vegetables, grains, and raw and pasteurized milk that can survive most food processing methods. Since spores cannot be inactivated by LTLT (low temperature long time) or HTST (high temperature short time) milk pasteurization methods, they are often responsible for food poisoning. However, UHT (ultra high temperature) processing completely kills the spores in raw milk by heating it to temperatures above $130^{\circ}C$ for a few seconds, and thus, the UHT method is popularly used for milk processing worldwide.

• 동아시아식생활학회지
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• 제23권1호
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• pp.61-68
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• 2013

This study tested the development of bechamel sauce with different ratios of soy milk to milk(0:4, 1:3, 1:1, 3:1, 4:0) to examine changes in quality characteristics. Proximate composition analysis showed a decrease in salinity with increasing amounts of soy milk, while the moisture content and, density increases. The highest pH values were found for a 1:1 ratio of soy milk to milk (S2) and the lowest pH values were found for a 0:4 ratio of soy milk to milk (CON). The L-value decreased, while a and b values increased with increasing amounts of soy milk. In the stability test, segregation occurred in CON after 5 days, while the highest segregation occurred at a 4:0 ratio of soy milk to milk (S4). The sensory evaluation results showed that the color, thickness, savory flavor, and savory taste increased with increasing amounts of soy milk. In the acceptance test, a 1:3 ratio of soy milk to milk (S1) and a 1:1 ratio of soy milk to milk (S2) had the highest acceptance scores (p<0.001) for appearance, taste, texture, and overall acceptance.

• Journal of Dairy Science and Biotechnology
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• 제15권1호
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• pp.53-57
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• 1997

Hokkaido, as center of Japanese dairying, 3.48 million tons of raw milk which was about 40% of total production in Japan were produced from 11,400 farms in 1996. The average herd size and the annual volume of milking per head in Hokkaido were 78 head, 7,200kg, and the quality of raw milk also is much better than that of other area in Japan. Raw milk having less than 100,000/ml in viable count and less than 300,000/ml of somatic cell count were 99.6%, 93% respectively. In spite of producing large amount of high quality milk, only 26% of total amount was processed as market milk and 76% was used for making dairy products like butter, cheese and milk powder. Therefore, because of big difference in price between the raw milk for market milk and for dairy products. the income of dairy farms are much less comparing to other parts of Japan, where most of the raw milk are consumed as market milk.

• Food Science and Biotechnology
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• 제14권6호
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• pp.752-757
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• 2005

Changes in milk quality during storage of extended shelf life milk (ESL milk) and non-ESL milk were evaluated. No significant differences were observed between ESL and typical ultra high temperature-treated (UHT) milk in physicochemical properties including non-casein nitrogen (NCN) content, whey protein nitrogen index (WPNI), and L-ascorbic acid content. Low temperature and long time-treated milk (LTLT milk) had significantly higher NCN content and WPNI than those of UHT milk. In terms of microbial quality, yeast, molds, coliforms, and other bacteria were not detected in ESL milk during entire storage (21 days after expiration date) period at 4 and $25^{\circ}C$, while LTLT milk was more susceptible to microbial infection. Rats fed ESL milk resulted in significantly higher body weight, average daily gain, and feed efficiency than those given UHT milk. These results suggest ESL milk maintains better microbial quality than typical UHT milk, particularly during storage under extended refrigeration and at high temperature.

• Agribusiness and Information Management
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• 제6권2호
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• pp.32-39
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• 2014

The goal of this research was to develop a portable system that could be used to evaluate the quality of milk in real time at a raw milk production site. A real-time portable quality evaluation system for raw milk was developed to enable non-destructive quality evaluation of somatic cell count (SCC), fat, protein, lactose, and total solid (TS) in milk samples. A prediction model of SCC, fat, protein, lactose, and TS was constructed using partial least squares (PLS) and 200 milk samples were used to evaluate the prediction performance of the portable quality evaluation system and high performance spectroscopy. Through prediction model development and verification, it was found that the accuracy of high performance spectroscopy was 90% for SSC, 96% for fat, 96% for protein, 91% for lactose, and 97% for TS. In comparison, the accuracy of the portable quality evaluation system was relatively low, at 90% for SSC, 95% for fat, 92% for protein, 89% for lactose, 92% for TS. However, the measurement time for high performance spectroscopy was 10 minutes for 1 sample, while for the portable quality evaluation system it was 6 minutes. This means that the high performance spectroscopy system can measure 48 samples per day (8 hours), while the portable quality evaluation system can measure 80 (8 hours). Therefore, it was found that the portable quality evaluation system enables quick on-site quality evaluation of milk samples.